Innovative cryogenic processing for enhanced surface integrity characteristics of stainless steels

In this study, the influence of the orthogonal cutting on the surface integrity characteristics of 316L austenitic stainless steel material under liquid nitrogen (LN2) condition was investigated. For this purpose, machining tests were carried out by applying LN2 to the cutting tool rake and flank face separately, and using different cutting parameters. In addition to the cutting force, the response of surface integrity characteristics such as microstructure, microhardness, and x-ray diffraction (XRD) analysis to LN2 was compared with dry cutting. The findings showed that the effect of different positioning of the LN2 nozzle on the cutting force and microhardness of the material is significant. In particular, the application of liquid nitrogen through the rake face significantly increases the microhardness of the material, while machined specimen microstructure images show that application of LN2 from the flank surface causes more grain refinement and deformation on the machined surface, especially at low cutting speed.